As shown in the figure below, a small, solid, uniform ball is to be shot from point P so that it rolls smoothly along a horizontal path, up along a ramp, and onto a plateau. Then it leaves the plateau horizontally to land on a game board, at a horizontal distance d from the right edge of the plateau. The vertical heights are h1 = 4.70 cm and h2 = 1.60 cm. With what speed must the ball be shot at point P for it to land at d = 6.40 cm? m/s